In recent years, the information processing devices have become more multi-functional and one information processing device has become utilized for various purposes. In an image scanner, for example, a main scanner body with a reading portion for reading an image of an original is engaged in an attachable/detachable manner with a feeder feeding the original. A user can utilize the image scanner as a handy scanner by using the main scanner body in a detached state from the feeder.
In this case, if power is supplied to the side of the main scanner body via a code, for example, the feeder can be powered through a connector from the side of the main scanner body with no additional code provided for power supply to the feeder. With such an arrangement, the connection of the codes in use becomes simple and the device can be used more conveniently.
When power is supplied from the main scanner body to the feeder, however, if a power supply switch on the side of the main scanner body is left in an on-state at the time of attachment/detachment of the feeder to/from the main scanner body, an electric shock will be caused on the side of the feeder at the time of attachment/detachment and the internal circuit on the side of the feeder can be damaged.
To avoid such problem, a circuit component capable of enduring such electric shock may be mounted on the side of the feeder. This arrangement, however, may lead to a complexity of the structure on the feeder side and increase in cost.
Alternatively, it is possible to oblige the user to turn off the power supply switch on the side of the main scanner body at the time of attachment/detachment of the main scanner body to/from the feeder. Then, the damage on the circuit due to an electric shock caused by an unstable state of electrical connection of the connector at the time of attachment/detachment can be prevented. This solution, however, affects the operability of the device. In addition, according to this solution, the circuit would not be protected when the user attaches/detaches the feeder to/from the main scanner body by mistake while the power supply switch is in an on-state.
The present invention is made to solve the above described problems and an object of the present invention is to provide an image reading device capable of protecting an internal circuit at a low cost from generation of an electric shock at the time of attachment/detachment of the image reading unit and the sheet feeding device.